Ingot casting



Nov. Z5, 1958 G. FENTON ETAL INGOT CASTING Filed Oct. 22, 1955 Lid/VATTQQNEYS nited States Patent() 2,861,305 INGoT CASTING Geoffrey Fenton,Richmond, Sheiiield, and Reginald Mayorcas, Sheffield, England,assignors to The British Iron and Steel Research Association, London,England Application October 22, 1956, Serial No. 617,421 8 Claims. (Cl.22-147) This invention 'relates to ingot casting and is particularlyconcerned with a novel form of feeder head for use in the casting ofingots. It is applicable to the casting of any high melting point metalor alloy and particularly to the casting of steel ingots which is takenas an example in the following. Feeder heads are usually made of rebrickand are designed to contain a reservoir of molten steel for compensatingfor the shrinkage in the steel in the ingot mould itself and thereby forreducing the formation of pipe and consequential unsound metal. Owing tothe relatively large heat capacity of iirebrick, there are substantialheat losses from the steel in the head so that relatively large amountsof steel solidify on the surface of the head. The solidified steel iswasted as far as the casting is concerned; ideally, the head-,should bea perfect heat insulator so that there will be no solidiiication in thehead and the volume of molten steel in the head need only be justsufficient to compensate for shrinkage in the mould.

According to the present invention, a feeder head comprises a tubulararrangement of good heat insulating material protected from the moltenmetal by a lining of refractory material. The refractory lining iscapable of withstanding the'high temperatureconditions within the headwhile the heat-insulating material which normally is incapable ofstanding up to contact with the liquid steel prevents undue heattransfer from the steel and therefore a high rate of solidication. Thevolume of molten steel introduced into the head can therefore be smallerthan in the case of iireclay heads.

In a convenient form of the invention, the heat insulating material issupported by a metallic tubular member having the refractory lining onthe inner side. The refractory material protects the metal member whichotherwise would melt owing-to the low heat transfer properties of theinsulating material on the outside thereof. The head is designed toenable the refractory lining Vand the metal member itself to be easilyreplaced as they become damaged under the severe operating conditions.Thus the head may comprise an outer case of suitable tubular form havingan inwardly directed plate at or near its lower end `and an upwardlydirected lip on the inner edge of the plate and a removable lid on theupper end of the case. The tubular metal member is slipped into positionbehind the lip from the top of the case, the heat insulating material islocated between the case and the metal member 'and the refractory liningis located on the lip; the whole is then secured by the attachment ofthe lid.

This construction gives a simple feeder head which is very easy to usein practice. For example, the refractory lining when it becomesunserviceable can be replaced with very little more trouble than theroutine dressing of conventional rebrick heads; similarly any damage tothe tubular metal member forming the inner wall of the container for theheat insulating material can be rectified merely by replacing it by anew member.

nessres of the lining and the inner wall should 'lie between 1A; inchand 3A inch and between 6 inch and Mi inch respectively according to thesize of the ingot.

The heat insulating material may be vermiculite, slag wool ordiatomaceous earth, and the refractory'material may Ibe gannister, compolime gauged with Portland cement, reclay or insulating concrete.

The invention will be more readily understood lby way of example fromthe following description of one form of feeder'nead in accordancetherewith, reference being made to the accompanying drawing which is asectional i view through the head.

The head illustrated in the drawing is of truncated cone or pyramidshape and comprises a cast iron outer box 12 provided with an inwardlydirected plate 13 on its lower edge. The plate 13 in turn has a smallupturned lip 14 on its inner edge. A truncatedcone or pyramid shapedthin perforated sheet steel member 15 is dropped into the box`12 so thatit is held on and located by the outer face of lip 14'. The spacebetween the box 12 and the member 15 is then filled with a highly heatinsulating material 16 and a layer 17of refractory material is cast onthe `inner side of member 15 so as to rest on the lip 14,

the perforations assisting the keying of the refractory material to themember 15; instead of having the member 15 perforated,"'weldmetal studsmay be placed on the inner Wall of member 15 for the same purpose.Finally a detachable lid 18 is placed over the assembly.V To enable thehead tol be moved the case 12 is provided with handles 19.

The heat insulating material 16 may be any such material having a lowbulk density and a low thermal c o'nductivity and it is preferred thatthe bulk density Vshouldl not exceed 8 lbs. per cubic foot and thethermal conductivity should not exceed 0.5 B. t. u./sq. ft./hr./in./f1-.

Examples of suitable materials are vermiculite, slag Wool' I anddiatoma-ceous earth.

The refractory material should be capable of protecting the heatinsulating material from the heat of the cast ingot, but on the otherhand should have a low .thermal capacity. The thickness of the layer 17should therefore be kept as small as possible and preferably lies withinthe range 1A; inch to 3A; inch, depending on the size ofthe ingot.Suitable materials are gannister, compo, fireclay and insulatingconcrete. ln addition, the layer 17 may include exothermic material toprevent further the solidication of metal on the head. In this case, thelayer 17 may be constituted by a single layer of exothermic materialincluding refractory or by a layer of refractory between a layer ofexothermic material and the steel member 15.

The thickness of the steel member 15 is also kept to a minimum andshould lie within the range V16 in ch to 1A inch, depending on the ingotsize.

The feeder head may be used either with or without a top addition, whichif used reduces the heat loss through the top of the head. Preferably,immediately after teeming the ingot, a top addition of exothermicmaterial and/ or insulating material is made.

The design of the head facilitates the replacement of the refractorylayer 17 and the steel member 15 as these become damaged. In practice,it has been found that a 1A inch lining 17 of gannister lasts at leasttwo heats and the member 15 with a thickness of 1/8 inch shows no signof damage or deterioration after six heats. The vermiculite layer 16requires infrequent replacement if at all. When using 1a iireclay head,the whole head must be changed once in about fifteen heats.

The construction described above enables a Substantially smaller volumeof steel to be -used inthe head to ensure compensation for shrinkage andthe increased cost of the head over known forms is more than outweightedby this reduction in metal.

We claim:

1. 'A feeder head'comprising a tubular container which includes aremovable tubular metal inner wall, uncompacted heat insulating materiallocated in saidI container, and a thin refractory lining of small heatcapacity secured on and supported by the inside of said inner Wall toprotect saidinner wall and said insulating material from temperatureeffects.

2. A feeder head comprising a tubular container which consistsessentially in a tubular convergent metal outer,

wall, an annular metal base secured to said outer wall and projectinginwardly, and a tubular convergent metal inner wall removably supportedon said base and spaced from said outer wall; a thin refractory liningofsmall heat capacity, secured on and supported by the inside of saidinner wall; and uncompacted heat insulating material substantiallyfilling the space within said container between said outer wall and saidremovable inner wall.

3. A feeder head comprising a tubular container which consistsessentially in a tubular convergent metal outer wall, an inwardlyextending annular metal base integral with said outer wall and locatedat the bottom of said wall, an upwardly extending lip at the innerextremityv of said base and a tubular convergent removable metal innerwall supported on said base and retained by said lip on the outer sidethereof; uncompacted heat insulating material substantially filling saidcontainer; and a thin re-` fractory lining of small heat capacitysecured on and supported by the inside of said inner wall.

4. A feeder head comprising a tubular container which includes areplaceable tubular metal inner wall, uncompacted heat insulatingmaterial substantially filling said container, and a thin refractorylining of small heat capacity secured on and supported by the inside ofsaid inner wall.

5. A feeder head comprising a tubular container which includes aremovable tubular metal inner Wall, ver'mculite substantially fillingsaid container, and a thin refractory lining of small heat capacitysecured on and supported by the inside of said inner wall.

6. A feeder head as claimed in claim 5 in which said refractory liningis made from a material selected from the group consisting of gannister,compo, ireclay and insulating concrete.

7. A feeder head comprising a tubular container which includes aremovable tubular metal inner wall, uncompactedheat 'insulating materialsubstantially -lling said container, and a thin layer of refractorymaterial cast on the inside 'of said inner Wall, said refractorymaterial being yselectedfrom-the group consisting of ,gannis'ten compo,iireclay and insulating concrete.

8. A feeder head 'comprising a 'tubular container which consistsessentially in a convergent tubular metal outer wall, an inwardlyextending annular metal base integral with said outer wall and locatedat the bottom `oflsaid wall,.an upwardly extending lip at the innerextremity of said base, a tubular convergent removable metal inner wallretained by said lip on the outer Side thereof, anda 5detachable annularlid bridging said inner and outer walls 4at the top thereof; a quantityof'vermiculite substantially filling said container; and a thin layer ofa refractory material selected 'from the group consisting of 'gannistencompo, ireclay and insulating concrete cast on to the inside lsurfaceofsaid 'inner wall and supported by saidV lip.

References CitedY in the le of this patent UNITEDv STATES PATENTS1,388,534 viuage Aug. 23, 1921 1,394;415 Howard et al. oct. 18,19211,654,057 smith Dec. l27,1927 1,696,986A Trembour Jan. 1, k19291,738,600 Messier Dec. 10, 1929 1,900,066 Mathesius Mar. 7, 19331,921,729 Charman ..Y aE Y Y.. -f Aug. 8, l11933 1,982,490 Williams eta1. Nov. 27, 1934 2,231,813 'Mcnonaid Feb. 11,1941 2,462,256 -Charman etal Feb. 22, 1949 FOREIGN PATENTS 300,033 Great vBritain Nov. 8, 1928

